Wish invading mainland china is more like opportunistic land grap instead of very ahistorical battle of two titans. While it does happen a FEW time in history (Xiōngnú, White Hun, Göktürks) it definitely not something that very common in medieval era

Even Successful invasion from Jurchen and mongol people were done by slowly grabing (either by raid or forceful tributary demand) and holding territory in few decade before annihilating the last representative of existing mandate of heaven holder and claim the legitimicacy. The closest we could get for historical example would be manchu invasion that founded qing dynasty but that is too way long after medieval era.

Antifa are fascists tho XD. actively trying to police how others think with violence and I've even seen a video where one claimed the first ammendment was "not relevant" because he disagreed with a guy.

But see, that's just the problem. Antifa is half actually anti-fascists, half militant anarcho-communists. And of the half that is actually anti-fascist, about 25% of them just want to see the world burn.

horse skirmisher, particulary berber jinetes is very viable tactic to counter other mounted troops also. In fact try to combine it with fast very light lancer to counter horse archer. Although you need to be careful when eccountering tighter formation.